Rukasov, V. I. “Best <em class="a-Plus-plus">n</Em&gt;-Term Approximations in Spaces With Nonsymmetric Metric”. Ukrains’kyi Matematychnyi Zhurnal 55, no. 4 (April 25, 2003): 500-509. Accessed May 18, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/3923.